After the first kind of education they received at home, at age 15, the young man entered the Calmecas, the priests were in charge. This educational institution was directed to the pipitlin class also known as the nobles. However there is some reference of lower class young people who had access to the Calmecac, thanks to their intelligence and dedication. The priests were equally chosen without taking into account the lineage but in turn counted on the constumbres and doctrines.
The education of Calmecac was very severe and prepraba the students to be priests or high functions of the state. There were many of them centers of high learning and most of the time there was always one next to a certain temple, when the young person enrolled in his school was put under great discipline as for example, when they had frequent and rigorous fasts. Many nights they went up a hill and offered incense to the Gods while punishing themselves alone with the sharp points of the Magueys. They were subject to the ideals of the priesthood with a renunciation of themselves, study of the stars, contemplative wisdom and chastity. The main divinity of these centers or temples was Quetzalcotal, god of self-sacrifice and penance of the arts and culture.